In:
Canadian Journal of Chemistry, Canadian Science Publishing, Vol. 79, No. 2 ( 2001-02-01), p. 174-182
Abstract:
A series of new chromophores, styryl-parent end-capped with various donors, and with barbituric acid, methyl-pyridinium, and methyl-quinolinium as the acceptors, have been synthesized and characterized by element analysis or X-ray diffraction. Using the Z-scan system, their two-photon absorption (TPA) cross-section values (δ) have been determined under excitation with 10 Hz, and 1064 nm, 35 ps mode-locked Nd:YAG laser pulse in DMF with d o = 0.05 M. The effective δ value is as high as 10.9 × 10 48 cm 4 s per photon for trans-4-(4'-N,N-diphenyl amino) styryl-N-methyl quinolinium iodide (DPASQI). The δ value increases from barbituric acid- to pyridinium- to quinolinium-derivatives apparently due to the increase in both the conjugated degree and planarity; however, when the acceptor is fixed, the δ value increases from dialkyl amino groups to diphenyl amino groups even though the latter is a weaker donor than the dialkyl amino groups. Theoretical calculations confirm that the increased distortion from planarity for the barbituric acid derivative makes its δ value decrease. The relatively large δ value for quinolinium- or pyridinium-derivatives originates from larger intramolecular charge transfer, which can be characterized by the difference of dipole moment (Δµ ge ) between the S 0 and S 1 , and the transition dipole moment (M ee' ) between S 1 and S 2 .Key words: two-photon absorption, intramolecular charge transfer, styryl-quinolinium, styryl-pyridinium, styryl-barbituric acid.
Type of Medium:
Online Resource
ISSN:
0008-4042
,
1480-3291
Language:
English
Publisher:
Canadian Science Publishing
Publication Date:
2001
detail.hit.zdb_id:
1482256-8
Permalink
